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Voltage Issues

Measure voltage at the exact same place as the instrument is powered to the same ground point with a known good voltmeter. Reading should agree to within 1/2 volt. If not return for repair.

EDM-700/800/760 = 1 amp surge upon startup – Nominally 1/2 amp(.5) for 12v systems and 1/4 amp(.25) for 14V and 28V systems. (Use a 5 AMP circuit breaker.- per Joe 12/14/07)

EDM-900/930/950 = 1 amp at startup – then will level at 1/2 amp. (Use a 5 AMP circuit breaker.)

VM-1000C = 1 amp at startup – then will level at 1/2 amp. (Use a 5 AMP circuit breaker.)

EDM-700/800: 10.5 to 35 v.  (Unit will remain on down to 10.5v)

EDM-760 needs to be above 11.5v. If voltage drops much lower the unit may reset itself.

EDM-930 needs 11.5 and above. (12V and above best. On 14v systems the EDM-930 may reset on engine start. Voltage drops too low. Can install aux battery power on J5 pin #13 – Rev D board.)

EDM-700/800/760 = 1 amp surge upon startup – Nominally 1/2 amp (.5) for 12v systems and 1/4 amp (.25) for 14V and 28V systems. (Use a 5 AMP circuit breaker. – per Joe 12/14/07)

EDM-900/930/950 = 1 amp at startup – then will level at 1/2 amp. (Use a 5 AMP circuit breaker.)

No.  Extra charge item. 200 amp max, 50 mV per 100 amps.

EDMs draw less than one ampere. A small voltage drop can be expected. A larger voltage drop can be caused by a bad connection on the power or ground leads or a faulty/corroded fuse or breaker.

Engine ground only – the same ground that the EGT probes are using – which is engine ground. Have them attach the black ground wire directly to the engine case. NOT panel ground, battery ground or airframe ground. These can vary from engine ground by 1/4v. This small voltage is can cause issues such as all EGT or CHT readings seem High or Low, or Unsteady.

0.5 voltage drop. EDMs draw less than one ampere. A small voltage drop can be expected. A larger voltage drop can be caused by a bad connection on the power of ground leads or a faulty/corroded fuse or breaker.